The present disclosure relates generally to cloud computing, and more particularly to using identity information for authentication of virtual machines.
Cloud computing services can provide computational capacity, data access, networking/routing and storage services via a large pool of shared resources operated by a cloud computing provider. Because the computing resources are delivered over a network, cloud computing is location-independent computing, with all resources being provided to end-users on demand with control of the physical resources separated from control of the computing resources.
Originally the term cloud came from a diagram that contained a cloud-like shape to contain the services that afforded computing power that was harnessed to get work done. Much like the electrical power we receive each day, cloud computing is a model for enabling access to a shared collection of computing resources—networks for transfer, servers for storage, and applications or services for completing work. More specifically, the term “cloud computing” describes a consumption and delivery model for IT services based on the Internet, and it typically involves over-the-Internet provisioning of dynamically scalable and often virtualized resources. This frequently takes the form of web-based tools or applications that users can access and use through a web browser as if it was a program installed locally on their own computer. Details are abstracted from consumers, who no longer have need for expertise in, or control over, the technology infrastructure “in the cloud” that supports them. Most cloud computing infrastructures consist of services delivered through common centers and built on servers. Clouds often appear as single points of access for consumers' computing needs, and do not require end-user knowledge of the physical location and configuration of the system that delivers the services.
The utility model of cloud computing is useful because many of the computers in place in data centers today are underutilized in computing power and networking bandwidth. People may briefly need a large amount of computing capacity to complete a computation for example, but may not need the computing power once the computation is done. The cloud computing utility model provides computing resources on an on-demand basis with the flexibility to bring it up or down through automation or with little intervention.
As a result of the utility model of cloud computing, there are a number of aspects of cloud-based systems that can present challenges to existing application infrastructure. First, clouds should enable self-service, so that users can provision servers and networks with little human intervention. Second, network access is necessary. Because computational resources are delivered over the network, the individual service endpoints need to be network-addressable over standard protocols and through standardized mechanisms. Third, multi-tenancy. Clouds are designed to serve multiple consumers according to demand, and it is important that resources be shared fairly and that individual users not suffer performance degradation. Fourth, elasticity. Clouds are designed for rapid creation and destruction of computing resources, typically based upon virtual containers. Provisioning these different types of resources must be rapid and scale up or down based on need. Further, the cloud itself as well as applications that use cloud computing resources must be prepared for impermanent, fungible resources; application or cloud state must be explicitly managed because there is no guaranteed permanence of the infrastructure. Fifth, clouds typically provide metered or measured service—like utilities that are paid for by the hour, clouds should optimize resource use and control it for the level of service or type of servers such as storage or processing.
Cloud computing offers different service models depending on the capabilities a consumer may require, including SaaS, PaaS, and IaaS-style clouds. SaaS (Software as a Service) clouds provide the users the ability to use software over the network and on a distributed basis. SaaS clouds typically do not expose any of the underlying cloud infrastructure to the user. PaaS (Platform as a Service) clouds provide users the ability to deploy applications through a programming language or tools supported by the cloud platform provider. Users interact with the cloud through standardized APIs, but the actual cloud mechanisms are abstracted away. Finally, IaaS (Infrastructure as a Service) clouds provide computer resources that mimic physical resources, such as computer instances, network connections, and storage devices. The actual scaling of the instances may be hidden from the developer, but users are required to control the scaling infrastructure.
One way in which different cloud computing systems may differ from each other is in how they deal with control of the underlying hardware and privacy of data. The different approaches are sometimes referred to a “public clouds,” “private clouds,” “hybrid clouds,” and “multi-vendor clouds.” A public cloud has an infrastructure that is available to the general public or a large industry group and is likely owned by a cloud services company. A private cloud operates for a single organization, but can be managed on-premise or off-premise. A hybrid cloud can be a deployment model, as a composition of both public and private clouds, or a hybrid model for cloud computing may involve both virtual and physical servers. A multi-vendor cloud is a hybrid cloud that may involve multiple public clouds, multiple private clouds, or some mixture.
Cloud computing systems include virtual machines that are instantiated from virtual machine images. One problem faced in cloud computing systems is handling security for newly instantiated virtual machine instances. The obvious solution to this problem is to store authentication information (e.g., ssh keys, login credentials, etc) directly in the virtual machine image. This would allow a virtual machine image to be authenticated immediately following instantiation. However, this type of authentication, based on the virtual machine instance's “possession” of a security credential, is inherently insecure; as the virtual machine images may be under the control of a party other than the one that created the image (e.g. the cloud services provider). So embedding login credentials in the image is not a practical solution. Another solution is the concept of administrative volumes, which are read-only information sources mounted automatically by new virtual machines. A newly instantiated virtual machine can read these volumes to obtain its initial configuration. However, read-only volumes are insufficient to provide all information needed by the newly instantiated virtual machine. For example, some virtual machines need information about the current state of the network upon instantiation. Storing this information in an administrative volume would require that volume to be constantly updated as network conditions changed, leading to the possibility of the virtual machine receiving stale data.
Accordingly, a system and method to authenticate newly instantiated virtual machine instances based on their identity would be desirable. Such a solution provides an appropriate level of security and a higher degree of flexibility to react to existing conditions in a cloud computing system.